It spends two hours choking you on soot so that one glimpse of a star lands like a punch. Studio 4°C builds Chimney Town as a tactile nightmare of grime and gaslight, then drops a garbage man with a beating heart into it, and Poupelle's patched-together bulk somehow moves with more warmth than any human in frame. The real cruelty is the system: a 4,000 meter wall, inquisitors who treat the word 'sky' as heresy, and currency engineered to rust so nobody can ever save enough to leave. Lubicchi refusing to stop believing his father Bruno wasn't a liar is the whole engine, and the film knows exactly what it's doing when it makes the town's laughter hurt worse than the beatings. Then the heart's origin lands, and the smoke finally parts. You'll be a mess about a trash monster. That's the deal.

Chimney Town sits inside a wall 4,000 meters high, and its many chimneys keep the air so full of smoke that nobody living there knows what the sky looks like. One night during the Halloween festival, a deliveryman loses the heart he was supposed to deliver. He searches the haze, then gives up, but the heart goes on beating where it fell. On Halloween night, Lubicchi, a young chimney sweep whose father died under the oppression of the Inquisitors, befriends a man magically formed from garbage and names him Poupelle. The Inquisitors work to suppress outside knowledge and the town's real history. As the pair draw attention, that danger and the scorn of some neighbors test their friendship. Together they set out to bring the truth to light and clear the smoke from the town's skies.